


Leverage

by KamehaSutra



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Accidental Voyeurism, F/M, Plot What Plot/Porn Without Plot, Pre-Time Skip, Secret Relationship, Semi-Public Sex, Teacher-Student Relationship
Language: English
Status: Completed
Published: 2021-01-01
Updated: 2021-01-01
Packaged: 2021-03-10 23:28:16
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 2,873
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28475430
Author URL: https://archiveofourown.org/users/KamehaSutra/pseuds/KamehaSutra
Summary: Sylvain tries to get some dirt on Dimitri and ends up learning way too much.
Relationships: Dimitri Alexandre Blaiddyd/My Unit | Byleth
Comments: 12
Kudos: 150





	Leverage

The Blue Lions are ill equipped to handle the heat wave that arrives in the last days of the Wyvern Moon. They swelter and sweat and fan themselves with folded sheets of parchment until Professor Byleth graciously cracks open the door and the one window behind her desk to try and get a cross breeze going. It’s not nearly enough to dispel the oppressive heat, but it’s definitely a nice gesture.

The heat wave drags on, as does everyone’s suffering. By the end of the week the even professor succumbs to the unseasonably hot weather and comes to class wearing the linen summer outfit provided to her by the monastery. Sylvain immediately notices that her legs look stunning in it, the exposed skin of her thighs perfectly framed above and below by her short skirt and tall boots. And he’s not the only one who’s noticed. Dimitri is usually the picture of the ideal student, paying rapt attention, asking questions and taking detailed notes, but today he seems much more interested in the watching professor's pert derriere wiggle around the room in that tiny skirt.

Sylvain can hardly fault him for that since anyone with eyes can see that Professor Byleth is an absolute knockout. But Dimitri has always has always made himself out to be above that sort of debasement and seeing him shamelessly ogle the professor is like seeing a dog walk on its hind legs. Sylvain’s greatest source of amusement comes when the professor invites Dimitri up to her desk for tutoring. The prince awkwardly stares into the professor’s eyes for the entire session as though he doesn’t trust himself to look anywhere else.

As entertaining as Dimitri is, Sylvain wastes no time hurrying outside as soon as they are dismissed, shuffling out into the courtyard with the rest of the Blue Lions students as they discuss how to enjoy their evening leisure time. Sylvain has no plans for the evening until one of his admirers shyly approaches extends him an invitation to dinner. He accepts and has a pleasant evening eating, flirting and enjoying female company until his dinner partner makes an offhand remark about the essay the professor had assigned them in class.

Sylvain has no recollection of any essay, having spent too much of his attention observing Dimitri’s antics. He reaches into his bag, searching for a stick of graphite so he can jot down the details of the assignment only to find his entire quill box missing, likely forgotten inside his desk in his haste to escape the stuffy lecture hall. He excuses himself as suavely as he can and then nearly sprints back to the Blue Lions’ classroom, hoping that he can get there before the professor locks up for the evening. The door is still unlocked when he arrives, and ever so slightly ajar, but the sound of low voices from inside the room makes him hesitate to go in. He leans forward cautiously, peeking through the small gap to see if it’s safe to enter.

The professor and Dimitri are inside, heads bowed together as Dimitri asks questions about one of the maps they had been discussing in class. There is something about the low timbre of the prince’s voice, the sinuous movements of his fingers as they trace over the professor’s map, the way his teeth worry at his lip as he awaits her responses to his questions, something that hints that he has more than battle strategies on his mind. The professor seems oblivious to the heavy atmosphere in the room, though, speaking when spoken to in a calm, even voice.

 _Is His Highness actually trying to put the moves on the professor?_ Sylvain wonders, utterly flabbergasted.

He must have gasped or reacted somehow, because Dimitri suddenly looks up, his eyes flickering suspiciously towards the door. Sylvain ducks out of view before he can be spotted, hiding just outside the entrance where he’s sure he will not be seen if Dimitri and the professor come out to investigate. There is silence for a moment and then, gradually, the talking inside resumes. Sylvain hurries back to his dinner date, writing instruments completely forgotten completely forgotten as a genius plan springs fully formed into his mind.

The next time Dimitri tries to lecture him on his flirting and philandering, he’ll just ask why it’s alright for Dimitri to stay back after class making heart-eyes at the professor. Dimitri, for fear of Sylvain “accidentally” mentioning his little crush in front of anyone who will listen, will agree to a mutually beneficial treaty where they both turn a blind eye to each others’ activities. All Sylvain needs to do is catch Dimitri in the act of flirting and shoot the prince one of his trademark Knowing Smiles.

Unfortunately, the professor comes to class the next day in her regular attire and Dimitri appears to lose interest after that. He still blushes and glances at the professor’s chest when she stops by his desk or singles him out for tutoring, but there are no more of the dark, wanting stares. When Dimitri lingers after class to ask questions about the lecture he does so in the company of Dedue or Ingrid, and he stands no closer to the professor than is appropriate.

Just as Sylvain starts to think that maybe he’s misread the situation and that maybe Dimitri is actually such a good student that his diligence can be mistaken for infatuation, another heat wave hits. Sylvain immediately notices the way the prince shifts uncomfortably throughout the lesson when confronted with sight of the professor’s legs, free of stockings and edged in form fitting linen. As usual the professor is completely oblivious, although she does stop by Dimitri’s desk a few times to remind him to stop daydreaming and keep his eyes on the board. Just as the professor is really getting into her explanation of the traditional weapons triangle and where bows, axes and fists fit into this system, the bell tolls to dismiss them for the evening.

There is a flurry of movement as everyone starts gathering up their bags and weapons, but Dimitri hasn’t stopped looking at the professor, his gloved finger restlessly stroking the bristles of his quill pen. The professor boldly looks back at him. Her lips quirk into a smug little smile. Then she plops down on top of her desk, picks up the stack of essays they had handed in earlier in the lecture and begins grading them.

Sylvain stands blinking in confusion as the other students begin to file out. _That definitely wasn’t nothing,_ he thinks. He’s never seen the professor smile once before, yet here she’s smiling at Dimitri now, clearly not as oblivious to the effect she has on Dimitri as Sylvain had thought. But that can only mean...

“Hey, Your Highness. How about you and I grab some dinner?” Sylvain offers, approaching Dimitri himself.

“Oh! Sylvain!” Dimitri furtively rearranges his cape so that the fabric drapes over his lap. “I appreciate the offer, but I’m afraid I must speak to the professor about some of the details of today’s lecture.”

“Right, right. About the weapon triangle,” Sylvain says. “You know, I think I understood the lesson pretty well for once. Maybe we can review it together over a sparring match?”

Dimitri blinks. “Oh! Er...well...we also have to discuss the procurement of supplies for next week’s sortie. House leader business, you understand.”

“Ah, of course,” Sylvain says, knowing that Dimitri would never pass up an opportunity to practice against a partner. “That’s definitely absolutely essential.”

“Well, yes...” Dimitri shuffles in his seat, made awkward by the ensuing silence and Sylvain’s knowing look. “Well...have a good evening, I suppose.”

Sylvain knows when he’s being dismissed. He waits until the other students have left the classroom before sauntering outside himself, making sure to leave the door slightly ajar so he has an opening to see and hear inside again. Students trickle out of the courtyard and into the monastery little by little, and Sylvain waits until he is alone before he risks sneaking back to the door of the Blue Lions’ classroom. He can see the two of them clearly through the gap between the doors if he presses his eye to it, although only just. The professor is still grading her papers. Dimitri is standing in front of her, almost uncomfortably close, but his posture is easy and relaxed with none of the stiffness Sylvain might expect from someone with Dimitri’s romantic history.

They chat for a while about the hot weather and the climate in Fhirdiad, until Dimitri tucks his fist under his chin and says, “At any rate. That was an interesting lesson today, professor.”

“Oh? I didn’t think it was that good,” the professor replies, setting down her stack of ungraded papers. “What did you find interesting about it?”

Slowly, deliberately, she uncrosses her long, bare legs and then recrosses them just as slowly on the other side. Dimitri swallows, his eyes tracking the movement with naked longing. The professor titters and meets his gaze directly with that smug little smile back on her face. “Is something wrong, Dimitri?” she says with feigned innocence

Sylvain almost exclaims in shock when Dimitri slips his fingers under the hem of the professor’s short skirt. The professor doesn’t cry out or scold him or back away, instead she lets out a whisper of a sigh and parts her thighs for him, which Dimitri takes as his cue to step between them and wind his free hand around the professor’s waist.

“I found it very interesting that you wore this to class again, after I so politely asked you not to last time,” the prince murmurs, toying with the fabric of the skirt as though deliberating whether or not he should tear it to pieces. “Are you trying to get me in trouble professor?”

“Oh? Whatever could you mean, Dimitri?” The professor says. She lets out what Sylvain assumes is a giggle, a strange huffing sort of laugh that trails off into a moan when Dimitri grips her ass hard with the hand that’s been drifting lower and lower down her back.

Dimitri silences her with his lips, claiming her mouth in a rough, possessive kiss that she eagerly reciprocates. She lets her hands wander hungrily over the prince’s body even as her legs lock tight around his waist, drawing him closer. Dimitri rewards her for her eagerness by removing his gauntlets and gloves, each set landing on the desk with a heavy thud. One of his hands twists into her hair and pulls, tugging her head back until she is forced to arch her spine for him.

“Still haven’t learned your lesson?” he asks in a voice that has gone low and gravelly. “I warned you what would happen if you tested my patience a second time.”

Sylvain feels a shiver run down his spine at the threat in Dimitri’s tone. He knows he should probably leave before someone comes along and catches him, but he’s seen and heard too much now and his feet will not carry him away. The professor squirms and writhes as Dimitri slips her panties off and begins to stroke between her legs, sometimes playing with her clit, sometimes dipping his fingers teasingly inside her. Sylvain can hear how ready she is from the wet noises her pussy makes against Dimitri’s hand.

 _Holy shit,_ Sylvain thinks, realizing that yes, he has definitely misunderstood the situation between Dimitri and the professor. He never would have dreamed that Prince Naive-and-Uptight himself would have the gall to sleep with their teacher. _What the hell? Why couldn’t he just wait until graduation?_ Sylvain wonders dumbly as he recalls all the times that Dimitri has seemed a little too eager to stay back after class, how many times he’s been found in the general area of the professor’s tent when they travel from battle to battle, his beatific smiles as he explains away the bruises that sometimes peek above the collar of his uniform. _He always said those came from training accidents,_ Sylvain thinks. He suddenly realizes that he is an idiot and that Dimitri has been gleefully yanking his chain for months now, lecturing Sylvain about decorum while he sneaks around and bangs the professor at every available opportunity.

The professor is absolutely gagging for it now, desperately fucking herself on Dimitri’s fingers as she chases her release. Dimitri chuckles darkly at her, fumbles with the fastenings at his waist with his free hand before pulling his cock out of his pants. The professor trembles eagerly at the sight of it, which Sylvain can hardly blame her for because it is quite a sight. Even from a distance, its length and girth are striking, even more so when it jumps eagerly in Dimitri’s hand as he gives it a few experimental strokes.

“Do you want it, professor?” Dimitri asks, squeezing his cock until it leaks precum onto the desk between them.

She nods emphatically.

“First, I want you to apologize for teasing me in class today,” he says.

The professor lets out a strangled cry when Dimitri slowly starts thrusting his fingers into her again. His thumb teases her sensitive clit, rubbing her until she is forced to cover her mouth to smother the moans that keep escaping her. Dimitri doesn’t relent, watching her as though transfixed as she wriggles and struggles to speak, punishing her with his fingers every time she tries and fails, keeping her at the edge of release until tears of frustration run down her cheeks.

“I’m waiting, professor.”

Byleth whines and mewls but eventually she gives the prince what he wants. “Ah...ah...I...I’m s-sorry!” The words come out in a weak, tremulous wail. “Please, Dimitri! I won’t do it again!”

Dimitri makes an amused noise, but is satisfied. He slips his fingers out of her, taking a moment to stroke himself slowly with the slick coating his hand, then his hands clamp down on the professor’s hips and he sinks his length into her in one firm thrust. The professor pinches her eyes shut, her back arching gracefully off her desk as Dimitri enters her. Dimitri gives her a moment’s respite to adjust to his size, playing fondly with her hair and peppering her face and neck with kisses.

“Do you like that, professor?” he asks. She doesn’t seem to hear him, too busy squirming against his grip when one of his hands slips between them to play with her clit again. “Is this as good for you as it is for me? Goddess, I love being inside of you. You’re so fucking tight.”

Sylvain has little time to be scandalized by Dimitri’s uncharacteristically foul mouth. The professor groans when Dimitri suddenly draws back and thrusts into her, slowly at first but soon quickening to a brutal place. The professor is so keyed up that she doesn’t last long like this, whimpering helplessly as Dimitri pounds her into the desk with single minded determination, her cries rising slowly in pitch until she suddenly lets out a high keening noise and falls apart on Dimitri’s cock. Her hips press up into his brutal thrusts as she rides out her orgasm, her legs squeezing even tighter around his waist. Dimitri trembles, his movements becoming erratic as he nears his own climax.

“Professor!” Dimitri gasps, completely delirious with pleasure now. He presses the professor tightly to his chest, burying his face in the crook of her neck as she writhes and kneads their bodies together. “Oh Goddess, that’s so fucking good. Please, I can’t hold on anymore… I… I…”

Sylvain decides to get the hell out of there before he can hear the end of that sentence, although he can hear some muffled groaning as he hurries out of the courtyard. He’s actually disappointed that he won’t get to see where His Highness ends up depositing his load, but the consequences of getting found out are honestly too awful to even think about. So awful that he probably won’t even be able to use this information for blackmail purposes. It isn’t until he lets himself into his room and flops down on his bed in defeat that he notices the awkward boner currently pitching a tent in his pants.

He stares at the ceiling for a while, trying his best to ignore it until it goes away. For his own sanity, he is going to forget he ever saw any of that. He is definitely not going to rub himself raw to the image of Dimitri railing the professor. He starts to think about lance training instead, going through the forms in his head, definitely not getting more and more erect at the idea that he has to go to class tomorrow and tolerate Dimitri and the professor’s stoic act knowing how noisy they both are in bed. His cock twitches in his pants, not wanting to be ignored.

 _Ah damn it_ , he sighs. Resigning himself to his fate, he undoes the buttons of his fly and pushes his pants down until his cock springs out to nestle against his stomach. _Well. Might as well get this over with._

**Author's Note:**

> im trying my hand at writing in general, but especially writing smut in 2021. follow me on twitter @kameha_sutra for even more garbage?


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